The present invention relates to methods for demonstrating techniques for lifting objects, and more particularly, to a method for demonstrating a lifting technique which reduces the likelihood of back injury.
Improper lifting techniques often result in back injuries. In addition, improper lifting techniques often decrease a person's potential lifting capacity. One traditional method for lifting objects is a technique known as the "backlift" (see FIG. 1). The backlift simply involves approaching an object, bending at the waist to grasp the object, and using the back muscles to return the body to an upright position. Backlifting stresses and strains the muscles, tendons and ligaments in the back and eventually causes a build-up of scar tissue and a permanent susceptibility to further back injuries.
Another traditional, well-known and often practiced method for lifting objects is a technique known as the "squatlift" (see FIG. 2). Squatlift training emphasizes placing the feet shoulder distance apart, keeping the back straight, and lifting with the legs. However, there are three inherent difficulties with this style of lifting. First, the lifter's heels quickly come off the floor and the lifter's body becomes unstably balanced on the balls of the feet. Second, the lifter's knees often get in the way of the object to be lifted, and the lifter is then forced to push the load farther away from the body's center of gravity than is desirable. The closer the load is held to the body the easier and less stressful the lift. Third, the squatlift requires the lifter's knee joints to be placed in a deep knee bend position wherein the angle between the upper leg and the lower leg is often less than 90.degree., thereby reducing the legs' efficiency and making it more difficult to unfold the knee from an angle less than 90.degree. back to a 180.degree. straight position. More particularly, the extremely short lever arm running from the patella (knee cap) to the tibial tuberosity (front of the shin bone) forces the quadricep muscles to work many times harder to hold the knee at any angle less than 90.degree. compared to an angle greater than 90.degree..